It is common to collect drainage water by use of a system of catch basins which are buried in the ground and are connected to a network of drain pipe. A problem is that the drainage water often includes debris and contaminants, and sometimes oil and grease. It is not desirable for these contaminants to get into the drain water which is expect to eventually reenter the earth's rivers, etc. which include fish, etc. There is a need for an effective and economic system for removing the debris and contaminants from the drainage water. The main object of this invention is to fill this need by providing a filter system installable into the catch basins for catching the debris and contaminants and removing them from the drainage water. It is a further object of the present invention to provide such a filter system which is easy to install, remove and maintain.